Flexovit ALUSHARK flap discs are made with premium aluminum oxide grain on a durable poly-cotton cloth, with a calcium sterate coating to resist loading and glazing when working on softer metals. This increases both the grinding speed and the disc life over regular zirconia or ceramic flap discs in these applications AluShark flap discs are designed for grinding, blending, and finishing of aluminum and other non-ferrous metals.